Photoacid generator compounds and compositions

ABSTRACT

The invention provides various ionic and non-ionic photoacid generator compounds. Photoresist compositions that include the novel ionic and non-ionic photoacid generator compounds are also provided. The invention further provides methods of making and using the photoacid generator compounds and photoresist compositions disclosed herein. The compounds and compositions are useful as photoactive components in chemically amplified resist compositions for various microfabrication applications.

RELATED APPLICATIONS

This application is a continuation under 35 U.S.C. 111(a) ofInternational Application No. PCT/US2007/009714, filed Apr. 23, 2007 andpublished in English as WO 2007/124092 on Nov. 1, 2007, which claimspriority from U.S. Provisional Application No. 60/793,988, filed Apr.21, 2006, which applications and publication are incorporated herein byreference.

BACKGROUND OF THE INVENTION

Several acid-catalyzed chemically amplified resist compositions havebeen developed. Chemically amplified resist compositions generallyinclude a photosensitive acid (“photoacid”) generator (PAG) and an acidsensitive polymer (resist). Upon exposure to radiation (e.g., x-rayradiation, ultraviolet radiation), the photoacid generator, by producinga proton, creates a photo-generated catalyst (usually a strong acid)during the exposure to radiation. During a post-exposure bake (PEB), theacid may act as a catalyst for further reactions. For example, the acidgenerated may facilitate the deprotection or cross-linking in thephotoresist. Generation of acid from the PAG does not necessarilyrequire heat. However, many known chemically amplified resists require apost-exposure bake (PEB) to complete the reaction between the acidmoiety and the acid labile component. Chemical amplification type resistmaterials include positive working materials that leave unexposedmaterial with the exposed areas removed and negative working materialsthat leave exposed areas with the unexposed areas removed.

Photoacid generators (PAGs) play a critical role in chemically amplifiedresist systems. Among the various classes of ionic and nonionic PAGsthat have been developed, one of the most widely used classes is theperfluorinated onium salts. Recently, government action has renderedmany of the most effective PAGs no longer commercially viable, includingthose based on perfluorooctyl sulfonates (PFOS). In addition toenvironmental concerns, the PFOS-based PAGs are a concern due to theirfluorous self-assembly and their diffusion characteristics at smallerdimensions. Previous efforts to develop new PAGs have focused mainly onimproving the photosensitive onium cation side to increase the quantumyield or to improve absorbance. The nature of the photoacid producedupon irradiation of the PAG is directly related to the anion of theionic PAG. Difference in acid strength, boiling point, size,miscibility, and stability of the photoacid produced can affectparameters related to photoresist performance, such as deprotection (orcross-linking) efficiency, photospeed, post-exposure bake (PEB)sensitivity, post-exposure delay (PED) stability, resolution, standingwaves, image profiles, and acid volatility. Because PFOS-based PAGs arebeing phased out and current commercial PAGs have significant drawbackswith respect to the previously mentioned properties, new PAGs that canhelp resolve these environmental and performance issue are needed.

SUMMARY OF THE INVENTION

One aspect of the present invention relates to the anionic component ofionic photoacid generators (PAGs). By designing new sulfonate anions,the homogeneous distribution of the PAG in a resist can be improved andappropriate mobility of the photogenerated acid can be obtained. At thesame time, these PAGs with new sulfonate anions can favorably addressenvironmental issues, including the need to reduce or eliminate the useof PFOSs.

To address environmental concerns related to the use of PFOS PAGs,sulfonic acids have been developed that contain fewer fluorinatedcarbons than typically found in PFOS. Perfluoro segments have beenreplaced with various functional groups that maintain the strongpolarization of the acid (i.e., pKa), control the size, and aid filmformation and compatibility with the matrix resin. In contrast to PFOS,the new PAGs with novel fluoro-organic sulfonate anions contain variousfunctional groups that allow them to degrade by chemical or physicalmodes to produce relatively short fluorine containing molecules. Thesenew PAGs are expected to be non-bioaccumalitive and environmentallyfriendly so there is less impact on the environment and on livingorganisms.

The present invention is also directed to a new approach to produceenvironmentally friendly photoacid generators (PAGs) having anions thatcomprise either short or no perfluoroalkyl chain (no-PFOS) attached to avariety of functional groups. The photoacid generators of the presentinvention can be formed from onium salts and various derivativecompounds, for example, as illustrated in formula I:

wherein

A₁ is I or S;

n₁ is 2 when A₁ is I, and n₁ is 3 when A₁ is S;

each R₀ is independently alkyl, cycloalkyl, heterocycle, aryl, orheteroaryl, each optionally substituted with one to about fivesubstituents;

A₂ is O or N;

n₂ is 1 when A₂ is 0 and n₂ is 2 when A₂ is N;

R_(f) is a diradical carbon chain comprising one to about 20 carbonatoms wherein the chain is optionally interrupted by one to five oxygenatoms, and each carbon atom is substituted with zero to two halo groups,or R_(f) is a direct bond;

each R₁ is independently H, alkyl, cycloalkyl, heterocycle, aryl, orheteroaryl;

n₃ is 0 to about 10;

n₄ is 1 or 2;

n₅ is 0 to 7; and

any aryl or heteroaryl is optionally substituted with one to five halo,(C₁-C₆)alkyl, alkoxy, acyl, alkoxycarbonyl, alkoxyacyl, acyloxy,trifluoromethyl, trifluoromethoxy, hydroxy, cyano, carboxy, nitro, or—N(R²)₂ groups;

any alkyl, cycloalkyl, heterocycle, aryl, or heteroaryl is optionallysubstituted with one to five halo, (C₁-C₆)alkyl, alkoxy, acyl,alkoxyacyl, acyloxy, trifluoromethyl, trifluoromethoxy, hydroxy, cyano,carboxy, nitro, —N(R²)₂, or oxo groups; and

each R² is independently H, alkyl, aryl, acyl, or aroyl.

Specific values for R₀ include aryl and heteroaryl, more specifically,phenyl, or pyridyl.

The diradical carbon chain comprising one to about 20 carbon atoms canhave about 2 to about 15 carbon atoms, or about 4 to about 10 carbonatoms in the chain, excluding heteroatom interruptions. In variousembodiments, R_(f) is substituted with two fluoro groups. In otherembodiments, R_(f) is a direct bond. In yet other embodiments, R_(f)includes at least four fluoro groups, or at least eight fluoro groups.R_(f) can also be —(CF₂)_(n)— wherein n is 1, 2, 3, 4, 5, 6, 7, or 8,—C(CF₃)₂—, —(CF₂)—O—(CF₂)₂—O—(CF₂)—, —(CF₂)₂—O—(CF₂)₂—, or a directbond.

In various embodiments, n₃ is 1. In certain embodiments, n₄ is 1. Insome embodiments, n₅ is 0, or n₅ is 1 and R¹ is (C₁-C₈)alkyl. Thevariable n₅ can also be 1 and R¹ can be methyl, in either the R or Sstereoisomeric conformation.

The present invention is also directed to a new approach to produceenvironmentally friendly photoacid generators (PAGs) that are non-ionicand that comprise either short or no perfluoroalkyl chains (no-PFOS)attached to a variety of functional groups. The photoacid generators ofthe present invention are formed from various chromophoric moieties andorganic or partially fluoroorganic moieties, and their derivatives, forexample, as illustrated in formula II. Accordingly, the inventionprovides PAGs, including compounds of formula II:

wherein

R₀ is alkyl, cycloalkyl, heterocycle, aryl, or heteroaryl, optionallysubstituted with one to about five substituents;

R₁ and R₂ are each independently H, alkyl, cycloalkyl, heterocycle,aryl, or heteroaryl;

G¹ is H, halo, hydroxy, nitro, cyano, trifluoromethyl, ortrifluoromethoxy;

each G² is independently alkyl, cycloalkyl, heterocycle, aryl,heteroaryl, halo, alkoxy, acyl, alkoxycarbonyl, alkoxyacyl, acyloxy,trifluoromethyl, trifluoromethoxy, hydroxy, cyano, carboxy, nitro, or—N(R²)₂ wherein each R² is independently H, alkyl, aryl, acyl, or aroyl;

n is 0, 1, 2, 3, or 4; and

any alkyl, cycloalkyl, heterocycle, aryl, or heteroaryl is optionallysubstituted with one to five halo, (C₁-C₆)alkyl, alkoxy, acyl,alkoxyacyl, acyloxy, trifluoromethyl, trifluoromethoxy, hydroxy, cyano,carboxy, nitro, —N(R²)₂, or oxo groups.

The variable R₀ can be optionally substituted aryl. R₀ can also beoptionally substituted phenyl. For example, the aryl (or phenyl) can besubstituted with one or more substituents as described in the DetailedDescription below.

In various embodiments, R² can be H. In certain embodiments, R¹ is notH. In some embodiments, G¹ can be nitro. In such embodiments, G¹ can benitro at the ortho position, or alternatively, the substitution can bemeta or para to the chain attachment.

The variable G² can be F or —CF₃.

The compound of formula II can be substituted with at least 2 fluorogroups, preferably 3-6 fluoro groups. In some embodiments, the compoundis substituted with at least 3 fluoro groups, preferably 4-6 fluorogroups.

Thus, the invention also provides a compound of formula III:

Additionally, a compound of formula III can be the compound

The invention also provides methods of preparing the compounds andcompositions described herein.

Each of the compounds of the invention can be used to prepare a chemicalamplification type resist composition that includes the photoacidgenerator. The chemical amplification type resist composition caninclude a resin that changes its solubility in an alkaline developerwhen contacted with an acid. Other compounds can be added to thecomposition, for example, compounds capable of generating an acid uponexposure to radiation other than a compound of formula I or II. Thechemical amplification type resist composition can further include abasic compound.

Finally, the invention provides a method to form a pattern comprising:

a) applying a resist composition that includes a compound of formula Ior II onto a substrate to provide a substrate with a coating;

b) heat treating the coating and exposing the coating to high energyradiation or electron beam through a photo-mask; and

c) optionally heat treating the exposed coating and developing thecoating with a developer.

The compounds and onium salts of the present invention provide aphotoacid generator for chemical amplification type resist compositionscomprising the compounds or onium salts described above.

In one embodiment, the invention provides: a chemical amplification typeresist composition comprising (i) a resin that changes its solubility inan alkaline developer under the action of an acid, and (ii) theaforementioned photoacid generator (PAG) that generates an acid uponexposure to radiation.

In another embodiment, the invention provides: a chemical amplificationtype resist composition comprising (i) a resin that changes itssolubility in an alkaline developer under the action of an acid, (ii)the aforementioned photoacid generator (PAG) that generates an acid uponexposure to radiation, and (iii) a compound capable of generating anacid upon exposure to radiation, other than component (ii). The resistcomposition may further include (iv) a basic compound and/or (v) acarboxyl group-containing compound.

Additionally, the present invention provides a process for forming apattern, including applying a resist composition described herein onto asubstrate to form a coating; heat treating the coating and exposing thecoating to high energy or electron beam through a photo-mask; optionallyheat treating the exposed coating, and developing the coating with adeveloper.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the sensitivity of various photoacid generators at254 nm.

FIG. 2 illustrates general structures of ionic PAGs, according tovarious embodiments. The values listed for the variables in FIG. 2 arerepresentative of certain embodiments; other embodiments may includeother substituents as defined herein.

FIG. 3 illustrates general structures of nonionic PAGs wherein box ashows representative chromophore moieties and box b shows representativefluorinated groups. The values listed for the variables in FIG. 3 arerepresentative of certain embodiments; other embodiments may includeother substituents as defined herein.

DETAILED DESCRIPTION

As used herein, the following terms and expressions have the indicatedmeanings. It will be appreciated that the compounds of the presentinvention can contain asymmetrically substituted carbon atoms, and canbe isolated in optically active or racemic forms. It is well known inthe art how to prepare optically active forms, such as by resolution ofracemic forms or by synthesis, from optically active starting materials.All chiral, diastereomeric, racemic forms and all geometric isomericforms of a structure are intended, unless the specific stereochemistryor isomeric form is specifically indicated.

“Stable compound” and “stable structure” are meant to indicate acompound that is sufficiently robust to survive isolation to a usefuldegree of purity from a reaction mixture, and formulation into anefficacious therapeutic agent. Only stable compounds are contemplated byand employed in the present invention.

“Substituted” is intended to indicate that one or more (e.g., 1, 2, 3,4, or 5; preferably 1, 2, or 3; and more preferably 1 or 2) hydrogenatoms on the atom indicated in the expression using “substituted” isreplaced with a selection from the indicated group(s), provided that theindicated atom's normal valency is not exceeded, and that thesubstitution results in a stable compound. Suitable indicated groups(referred to as “substituents”) include, e.g., alkyl, alkenyl, alkynyl,alkoxy, halo, haloalkyl, hydroxy, hydroxyalkyl, aryl, heteroaryl,heterocycle, cycloalkyl, alkanoyl, alkoxycarbonyl, amino, alkylamino,dialkylamino, trifluoromethylthio, difluoromethyl, acylamino, nitro,trifluoromethyl, trifluoromethoxy, carboxy, carboxyalkyl, keto, thioxo,alkylthio, alkylsulfinyl, alkylsulfonyl, and cyano. Alternatively, thesuitable indicated groups can include, e.g., —X, —R, —O⁻, —OR, —SR, —S⁻,—NR₂, —NR₃, ═NR, —CX₃, —CN, —OCN, —SCN, —N═C═O, —NCS, —NO, —NO₂, ═N₂,—N₃, NC(═O)R, —C(═O)R, —C(═O)NRR, —S(═O)₂O⁻, —S(═O)₂OH, —S(═O)₂R,—OS(═O)₂OR, —S(═O)₂NR, —S(═O)R, —OP(═O)(OR)₂, —P(═O)(OR)₂, —P(═O)(O⁻)₂,—P(═O)(OH)₂, —C(═O)R, —C(═O)X, —C(S)R, —C(O)OR, —C(O)O⁻, —C(S)OR,—C(O)SR, —C(S)SR, —C(O)NRR, —C(S)NRR, —C(NR)NRR, where each X isindependently a halogen: F, Cl, Br, or I; and each R is independently H,alkyl, aryl, heterocycle, protecting group or prodrug moiety. When asubstituent is a keto (i.e., ═O) or thioxo (i.e., ═S) group, then 2hydrogens on the atom are replaced. One or more of the aforementionedsubstituents can also be excluded from a compound or formula of theinvention.

One diastereomer may display superior activity compared with the other.When required, separation of the racemic material can be achieved byhigh pressure liquid chromatography (HPLC) using a chiral column or by aresolution using a resolving agent such as camphonic chloride as inThomas J. Tucker, et al., J. Med. Chem. 1994 37, 2437-2444. A chiralcompound may also be directly synthesized using a chiral catalyst or achiral ligand, e.g. Mark A. Huffman, et al., J. Org. Chem. 1995, 60,1590-1594.

The term “alkyl” refers to a monoradical branched or unbranchedsaturated hydrocarbon chain preferably having from 1 to 10 carbon atoms,preferably 1 to 6 carbon atoms, and more preferably from 1 to 4 carbonatoms. Examples are methyl (Me, —CH₃), ethyl (Et, —CH₂CH₃), 1-propyl(n-Pr, n-propyl, —CH₂CH₂CH₃), 2-propyl (i-Pr, i-propyl, —CH(CH₃)₂),1-butyl (n-Bu, n-butyl, —CH₂CH₂CH₂CH₃), 2-methyl-1-propyl (i-Bu,i-butyl, —CH₂CH(CH₃)₂), 2-butyl (s-Bu, s-butyl, —CH(CH₃)CH₂CH₃),2-methyl-2-propyl (t-Bu, t-butyl, —C(CH₃)₃), 1-pentyl (n-pentyl,—CH₂CH₂CH₂CH₂CH₃), 2-pentyl (—CH(CH₃)CH₂CH₂CH₃), 3-pentyl(—CH(CH₂CH₃)₂), 2-methyl-2-butyl (—C(CH₃)₂CH₂CH₃), 3-methyl-2-butyl(—CH(CH₃)CH(CH₃)₂), 3-methyl-1-butyl (—CH₂CH₂CH(CH₃)₂), 2-methyl-1-butyl(—CH₂CH(CH₃)CH₂CH₃), 1-hexyl (—CH₂CH₂CH₂CH₂CH₂CH₃), 2-hexyl(—CH(CH₃)CH₂CH₂CH₂CH₃), 3-hexyl (—CH(CH₂CH₃)(CH₂CH₂CH₃)),2-methyl-2-pentyl (—C(CH₃)₂CH₂CH₂CH₃), 3-methyl-2-pentyl(—CH(CH₃)CH(CH₃)CH₂CH₃), 4-methyl-2-pentyl (—CH(CH₃)CH₂CH(CH₃)₂),3-methyl-3-pentyl (—C(CH₃)(CH₂CH₃)₂), 2-methyl-3-pentyl(—CH(CH₂CH₃)CH(CH₃)₂), 2,3-dimethyl-2-butyl (—C(CH₃)₂CH(CH₃)₂),3,3-dimethyl-2-butyl (—CH(CH₃)C(CH₃)₃. The alkyl can be unsubstituted orsubstituted.

The term “alkenyl” refers to a monoradical branched or unbranchedpartially unsaturated hydrocarbon chain (i.e. a carbon-carbon, sp²double bond) preferably having from 2 to 10 carbon atoms, preferably 2to 6 carbon atoms, and more preferably from 2 to 4 carbon atoms.Examples include, but are not limited to, ethylene or vinyl (—CH═CH₂),allyl (—CH₂CH═CH₂), cyclopentenyl (—C₅H₇), and 5-hexenyl(—CH₂CH₂CH₂CH₂CH═CH₂). The alkenyl can be unsubstituted or substituted.

The term “alkynyl” refers to a monoradical branched or unbranchedhydrocarbon chain, having a point of complete unsaturation (i.e. acarbon-carbon, sp triple bond), preferably having from 2 to 10 carbonatoms, preferably 2 to 6 carbon atoms, and more preferably from 2 to 4carbon atoms. This term is exemplified by groups such as ethynyl,1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-hexynyl,2-hexynyl, 3-hexynyl, and the like. The alkynyl can be unsubstituted orsubstituted.

“Alkylene” refers to a saturated, branched or straight chain hydrocarbonradical of 1-18 carbon atoms, and having two monovalent radical centersderived by the removal of two hydrogen atoms from the same or twodifferent carbon atoms of a parent alkane. Typical alkylene radicalsinclude, but are not limited to, methylene (—CH₂—) 1,2-ethyl (—CH₂CH₂—),1,3-propyl (—CH₂CH₂CH₂—), 1,4-butyl (—CH₂CH₂CH₂CH₂—), and the like. Thealkynyl can be unsubstituted or substituted.

“Alkenylene” refers to an unsaturated, branched or straight chainhydrocarbon radical of 2-18 carbon atoms, and having two monovalentradical centers derived by the removal of two hydrogen atoms from thesame or two different carbon atoms of a parent alkene. Typicalalkenylene radicals include, but are not limited to, 1,2-ethylene(—CH═CH—). The alkenylene can be unsubstituted or substituted.

“Alkynylene” refers to an unsaturated, branched or straight chainhydrocarbon radical of 2-18 carbon atoms, and having two monovalentradical centers derived by the removal of two hydrogen atoms from thesame or two different carbon atoms of a parent alkyne. Typicalalkynylene radicals include, but are not limited to, acetylene (—C≡C—),propargyl (—CH₂C≡C—), and 4-pentynyl (—CH₂CH₂CH₂C≡CH—). The alkynylenecan be unsubstituted or substituted.

The term “alkoxy” refers to the groups alkyl-O—, where alkyl is definedherein. Preferred alkoxy groups include, e.g., methoxy, ethoxy,n-propoxy, iso-propoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy,n-hexoxy, 1,2-dimethylbutoxy, and the like. The alkoxy can beunsubstituted or substituted.

The term “aryl” refers to an unsaturated aromatic carbocyclic group offrom 6 to 12 carbon atoms having a single ring (e.g., phenyl) ormultiple condensed (fused) rings, wherein at least one ring is aromatic(e.g., naphthyl, dihydrophenanthrenyl, fluorenyl, or anthryl). The arylcan be unsubstituted or substituted.

The term “cycloalkyl” refers to cyclic alkyl groups of from 3 to 10carbon atoms having a single cyclic ring or multiple condensed rings.Such cycloalkyl groups include, by way of example, single ringstructures such as cyclopropyl, cyclobutyl, cyclopentyl, cyclooctyl, andthe like, or multiple ring structures such as adamantanyl, and the like.The cycloalkyl can be unsubstituted or substituted.

The term “halo” refers to fluoro, chloro, bromo, and iodo. Similarly,the term “halogen” refers to fluorine, chlorine, bromine, and iodine.

“Haloalkyl” refers to alkyl as defined herein substituted by 1-4 halogroups as defined herein, which may be the same or different.Representative haloalkyl groups include, by way of example,trifluoromethyl, 3-fluorododecyl, 12,12,12-trifluorododecyl,2-bromooctyl, 3-bromo-6-chloroheptyl, and the like.

The term “heteroaryl” is defined herein as a monocyclic, bicyclic, ortricyclic ring system containing one, two, or three aromatic rings andcontaining at least one nitrogen, oxygen, or sulfur atom in an aromaticring, and which can be unsubstituted or substituted, for example, withone or more, and in particular one to three, substituents, selected fromalkyl, alkenyl, alkynyl, alkoxy, halo, haloalkyl, hydroxy, hydroxyalkyl,aryl, heterocycle, cycloalkyl, alkanoyl, alkoxycarbonyl, amino,alkylamino, dialkylamino, trifluoromethylthio, difluoromethyl,acylamino, nitro, trifluoromethyl, trifluoromethoxy, carboxy,carboxyalkyl, keto, thioxo, alkylthio, alkylsulfinyl, alkylsulfonyl andcyano. Examples of heteroaryl groups include, but are not limited to,2H-pyrrolyl, 3H-indolyl, 4H-quinolizinyl, 4nH-carbazolyl, acridinyl,benzo[b]thienyl, benzothiazolyl, β-carbolinyl, carbazolyl, chromenyl,cinnolinyl, dibenzo[b,d]furanyl, furazanyl, furyl, imidazolyl,imidizolyl, indazolyl, indolisinyl, indolyl, isobenzofuranyl,isoindolyl, isoquinolyl, isothiazolyl, isoxazolyl, naphthyridinyl,naptho[2,3-b], oxazolyl, perimidinyl, phenanthridinyl, phenanthrolinyl,phenarsazinyl, phenazinyl, phenothiazinyl, phenoxathiinyl, phenoxazinyl,phthalazinyl, pteridinyl, purinyl, pyranyl, pyrazinyl, pyrazolyl,pyridazinyl, pyridyl, pyrimidinyl, pyrimidinyl, pyrrolyl, quinazolinyl,quinolyl, quinoxalinyl, thiadiazolyl, thianthrenyl, thiazolyl, thienyl,triazolyl, and xanthenyl. In one embodiment the term “heteroaryl”denotes a monocyclic aromatic ring containing five or six ring atomscontaining carbon and 1, 2, 3, or 4 heteroatoms independently selectedfrom the group non-peroxide oxygen, sulfur, and N(Z) wherein Z is absentor is H, O, alkyl, phenyl or benzyl. In another embodiment heteroaryldenotes an ortho-fused bicyclic heterocycle of about eight to ten ringatoms derived therefrom, particularly a benz-derivative or one derivedby fusing a propylene, or tetramethylene diradical thereto.

“Heterocycle” as used herein includes by way of example and notlimitation those heterocycles described in Paquette, Leo A.; Principlesof Modern Heterocyclic Chemistry (W. A. Benjamin, New York, 1968),particularly Chapters 1, 3, 4, 6, 7, and 9; The Chemistry ofHeterocyclic Compounds, A Series of Monographs” (John Wiley & Sons, NewYork, 1950 to present), in particular Volumes 13, 14, 16, 19, and 28;and J. Am. Chem. Soc. (1960) 82:5566. In one specific embodiment of theinvention “heterocycle” includes a “carbocycle” as defined herein,wherein one or more (e.g. 1, 2, 3, or 4) carbon atoms have been replacedwith a heteroatom (e.g. O, N, or S).

Examples of heterocycles include, by way of example and not limitation:pyridyl, dihydroypyridyl, tetrahydropyridyl (piperidyl), thiazolyl,tetrahydrothiophenyl, sulfur oxidized tetrahydrothiophenyl, pyrimidinyl,furanyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, tetrazolyl,benzofuranyl, thianaphthalenyl, indolyl, indolenyl, quinolinyl,isoquinolinyl, benzimidazolyl, piperidinyl, 4-piperidonyl, pyrrolidinyl,2-pyrrolidonyl, pyrrolinyl, tetrahydrofuranyl, tetrahydroquinolinyl,tetrahydroisoquinolinyl, decahydroquinolinyl, octahydroisoquinolinyl,azocinyl, triazinyl, 6H-1,2,5-thiadiazinyl, 2H,6H-1,5,2-dithiazinyl,thienyl, thianthrenyl, pyranyl, isobenzofuranyl, chromenyl, xanthenyl,phenoxathinyl, 2H-pyrrolyl, isothiazolyl, isoxazolyl, pyrazinyl,pyridazinyl, indolizinyl, isoindolyl, 3H-indolyl, 1H-indazoly, purinyl,4H-quinolizinyl, phthalazinyl, naphthyridinyl, quinoxalinyl,quinazolinyl, cinnolinyl, pteridinyl, 4aH-carbazolyl, carbazolyl,β-carbolinyl, phenanthridinyl, acridinyl, pyrimidinyl, phenanthrolinyl,phenazinyl, phenothiazinyl, furazanyl, phenoxazinyl, isochromanyl,chromanyl, imidazolidinyl, imidazolinyl, pyrazolidinyl, pyrazolinyl,piperazinyl, indolinyl, isoindolinyl, quinuclidinyl, morpholinyl,oxazolidinyl, benzotriazolyl, benzisoxazolyl, oxindolyl, benzoxazolinyl,isatinoyl, and bis-tetrahydrofuranyl.

By way of example and not limitation, carbon bonded heterocycles arebonded at position 2, 3, 4, 5, or 6 of a pyridine, position 3, 4, 5, or6 of a pyridazine, position 2, 4, 5, or 6 of a pyrimidine, position 2,3, 5, or 6 of a pyrazine, position 2, 3, 4, or 5 of a furan,tetrahydrofuran, thiofuran, thiophene, pyrrole or tetrahydropyrrole,position 2, 4, or 5 of an oxazole, imidazole or thiazole, position 3, 4,or 5 of an isoxazole, pyrazole, or isothiazole, position 2 or 3 of anaziridine, position 2, 3, or 4 of an azetidine, position 2, 3, 4, 5, 6,7, or 8 of a quinoline or position 1, 3, 4, 5, 6, 7, or 8 of anisoquinoline. Still more typically, carbon bonded heterocycles include2-pyridyl, 3-pyridyl, 4-pyridyl, 5-pyridyl, 6-pyridyl, 3-pyridazinyl,4-pyridazinyl, 5-pyridazinyl, 6-pyridazinyl, 2-pyrimidinyl,4-pyrimidinyl, 5-pyrimidinyl, 6-pyrimidinyl, 2-pyrazinyl, 3-pyrazinyl,5-pyrazinyl, 6-pyrazinyl, 2-thiazolyl, 4-thiazolyl, or 5-thiazolyl.

By way of example and not limitation, nitrogen bonded heterocycles arebonded at position 1 of an aziridine, azetidine, pyrrole, pyrrolidine,2-pyrroline, 3-pyrroline, imidazole, imidazolidine, 2-imidazoline,3-imidazoline, pyrazole, pyrazoline, 2-pyrazoline, 3-pyrazoline,piperidine, piperazine, indole, indoline, 1H-indazole, position 2 of aisoindole, or isoindoline, position 4 of a morpholine, and position 9 ofa carbazole, or β-carboline. Still more typically, nitrogen bondedheterocycles include 1-aziridyl, 1-azetedyl, 1-pyrrolyl, 1-imidazolyl,1-pyrazolyl, and 1-piperidinyl.

“Carbocycle” refers to a saturated, unsaturated or aromatic ring having3 to 7 carbon atoms as a monocycle, 7 to 12 carbon atoms as a bicycle,and up to about 30 carbon atoms as a polycycle. Monocyclic carbocycleshave 3 to 6 ring atoms, still more typically 5 or 6 ring atoms. Bicycliccarbocycles have 7 to 12 ring atoms, e.g., arranged as a bicyclo [4,5],[5,5], [5,6] or [6,6] system, or 9 or 10 ring atoms arranged as abicyclo[5,6] or [6,6] system. Examples of carbocycles includecyclopropyl, cyclobutyl, cyclopentyl, 1-cyclopent-1-enyl,1-cyclopent-2-enyl, 1-cyclopent-3-enyl, cyclohexyl, 1-cyclohex-1-enyl,1-cyclohex-2-enyl, 1-cyclohex-3-enyl, phenyl, spiryl, adamantly, andnaphthyl.

The terms “cycloalkylene”, “carbocyclene”, “arylene”, “heterocyclene”,and “heteroarylene” refer to diradicals of the parent group. Forexample, “arylene” refers to an aryl diradical, e.g., an aryl group thatis bonded to two other groups or moieties.

The term “alkanoyl” refers to C(═O)R, wherein R is an alkyl group aspreviously defined.

The term “alkoxycarbonyl” refers to C(═O)OR, wherein R is an alkyl groupas previously defined.

The term “amino” refers to —NH₂, and the term “alkylamino” refers to—NR₂, wherein at least one R is alkyl and the second R is alkyl orhydrogen. The term “acylamino” refers to RC(═O)NH—, wherein R is alkylor aryl.

As to any of the above groups, which contain one or more substituents,it is understood, of course, that such groups do not contain anysubstitution or substitution patterns that are sterically impracticaland/or synthetically non-feasible. In addition, the compounds of thisinvention include all stereochemical isomers arising from thesubstitution of these compounds.

As used herein, “contacting” refers to the act of touching, makingcontact, or of bringing to immediate or close proximity, including atthe molecular level.

Resist Compositions

Upon use of a chemical amplification type positive-working resistcompositions, a resist film is formed by dissolving a resin having acidlabile groups as a binder and a compound capable of generating an acidupon exposure to radiation (“a photoacid generator”) in a solvent,applying the resist solution onto a substrate by a variety of methods,and evaporating off the solvent optionally by heating. The resist filmis then exposed to radiation, for example, deep UV radiation, through amask of a predetermined pattern. This is optionally followed bypost-exposure baking (PEB) for promoting acid-catalyzed reaction. Theexposed resist film is developed with an aqueous alkaline developer forremoving the exposed area of the resist film, obtaining a positivepattern profile. The substrate is then etched by any desired technique.Finally the remaining resist film is removed by dissolution in a removersolution or ashing, leaving the substrate having the desired patternprofile.

Chemical amplification type positive-working resist compositions adaptedfor KrF excimer lasers generally use a phenolic resin, for example,polyhydroxy-styrene, in which some or all of the hydrogen atoms ofphenolic hydroxyl groups are protected with acid labile protectivegroups. Onium salts, such as iodonium salts and sulfonium salts havingperfluorinated anions, are typically used as the photoacid generator. Ifdesired, the resist compositions can contains one or more additives, forexample, a dissolution inhibiting or promoting compound in the form of acarboxylic acid and/or phenol derivative having a molecular weight of upto about 3,000, in which some or all of the hydrogen atoms of carboxylicacid and/or phenolic hydroxyl groups are protected with acid labilegroups, a carboxylic acid compound for improving dissolutioncharacteristics, a basic compound for improving contrast, and asurfactant for improving coating characteristics.

Ionic photoacid generators, typically onium salts, can be advantageouslyused as the photoacid generator in chemical amplification type resistcompositions, especially chemical amplification type positive-workingresist compositions adapted for KrF excimer lasers. Ionic photoacidgenerators provide a high sensitivity and resolution and are free fromstorage instability.

A compound of formula I or II can be used as a photoacid generator in aresist material, especially chemical amplification type resistmaterials. The invention provides resist compositions comprising acompound of one of formulas I-II as the photoacid generator. The resistcompositions may be either positive- or negative-working. The resistcompositions of the invention include a variety of embodiments,including one or more of any of the following, in any combination:

1) a chemically amplified positive working resist composition comprising(A) a resin that changes its solubility in an alkaline developer underthe action of an acid, (B) a photoacid generator comprising a compoundof one of formulas I-II capable of generating an acid upon exposure toradiation, and (C) an organic solvent;

2) a chemically amplified positive working resist composition of 1)above further comprising (D) a photoacid generator capable of generatingan acid upon exposure to radiation other than component (B);

3) a chemically amplified positive working resist composition of 1) or2) further comprising (E) a basic compound;

4) a chemically amplified positive working resist composition of 1) to3) further comprising (F) an organic acid derivative;

5) a chemically amplified positive working resist composition of 1) to4) further comprising (G) a compound with a molecular weight of up toabout 3,000 that changes its solubility in an alkaline developer underthe action of an acid;

6) a chemically amplified negative working resist composition comprising(B) a photoacid generator comprising a compound of one of formulas I-IIcapable of generating an acid upon exposure to radiation, (H) analkali-soluble resin, an acid crosslinking agent capable of forming acrosslinked structure under the action of an acid, and (C) an organicsolvent;

7) a chemically amplified negative working resist composition of 6)further comprising (D) another photoacid generator;

8) a chemically amplified negative working resist composition of 6) or7) further comprising (E) a basic compound; as well as

9) a chemically amplified negative working resist composition of 6), 7)or 8) further comprising (J) an alkali-soluble compound with a molecularweight of up to about 2,500, up to about 5,000, or up to about 10,000.

Additionally, the invention provides a process for forming a pattern,comprising the steps of applying a resist composition described aboveonto a substrate to form a coating; heat treating the coating andexposing the coating to high energy radiation (for example, with awavelength of up to 300 nm) or electron beam through a photo-mask;

optionally heat treating the exposed coating, and developing the coatingwith a developer.

Various components of the compositions of the invention include thefollowing:

Component (A): Resin

Component (A) is a resin which changes its solubility in an alkalinedeveloper solution under the action of an acid. It is preferably, thoughnot limited thereto, an alkali-soluble resin having phenolic hydroxyland/or carboxyl groups in which some or all of the phenolic hydroxyland/or carboxyl groups are protected with acid-labile protective groups.

The alkali-soluble resins having phenolic hydroxyl and/or carboxylgroups include homopolymers and copolymers of p-hydroxystyrene,m-hydroxystyrene, α-methyl-p-hydroxystyrene, 4-hydroxy-2-methylstyrene,4-hydroxy-3-methylstyrene, methacrylic acid, and acrylic acid. Alsoincluded are copolymers in which units free of alkali-soluble sites suchas styrene, α-methylstyrene, acrylate, methacrylate, hydrogenatedhydroxystyrene, maleic anhydride and maleimide are introduced inaddition to the above-described units in such a proportion that thesolubility in an alkaline developer is not be extremely reduced.Substituents on acrylates and methacrylates may be any substituent thatdoes not undergo acidolysis. In one embodiment, the substituents arestraight, branched or cyclic (C₁-C₈)alkyl groups and aromatic groupssuch as aryl groups, but not limited thereto. In other specificembodiments, the substituents can be methyl, ethyl, propyl (normal oriso), butyl (normal or iso), cyclohexyl, etc., or combinations thereof.

Non-limiting examples of alkali-soluble resins are given below. Thesepolymers may also be used as the material from which the resin (A)(which changes its solubility in an alkaline developer under the actionof an acid) is prepared. These polymers may also be used as thealkali-soluble resin that serves as component (H), describedhereinbelow. Examples include poly(p-hydroxystyrene),poly(m-hydroxystyrene), poly(4-hydroxy-2-methylstyrene),poly(4-hydroxy-3-methylstyrene), poly(α-methyl-p-hydroxystyrene),partially hydrogenated p-hydroxystyrene copolymers,p-hydroxystyrene-α-methyl-p-hydroxystyrene copolymers,p-hydroxystyrene-α-methylstyrene copolymers, p-hydroxystyrene-styrenecopolymers, p-hydroxystyrene-m-hydroxystyrene copolymers,p-hydroxystyrene-styrene copolymers, p-hydroxystyrene-acrylic acidcopolymers, p-hydroxystyrene-methacrylic acid copolymers,p-hydroxystyrene-methyl methacrylate copolymers,p-hydroxystyrene-acrylic acid-methyl methacrylate copolymers,p-hydroxystyrene-methyl acrylate copolymers,p-hydroxy-styrene-methacrylic acid-methyl methacrylate copolymers,poly(methacrylic acid), poly(acrylic acid), acrylic acid-methyl acrylatecopolymers, methacrylic acid-methyl methacrylate copolymers, acrylicacid-maleimide copolymers, methacrylic acid-maleimide copolymers,p-hydroxystyrene-acrylic acid-maleimide copolymers, andp-hydroxystyrene-methacrylic acid-maleimide copolymers, as well asdendritic and hyperbranched polymers thereof, but are not limited tothese combinations.

The alkali-soluble resins or polymers should preferably have a weightaverage molecular weight (Mw) of about 3,000 to about 100,000. Manypolymers with Mw of less than about 3,000 do not perform well in heatresistance and film formation. Many polymers with Mw of more than about100,000 give rise to problems with respect to dissolution in the resistsolvent and developer. The polymer can have a dispersity (Mw/Mn) of upto about 3.5, and more preferably up to about 1.5. With a dispersity ofmore than about 3.5, resolution is sometimes lower than is desired.Although the preparation method is not critical, apoly(p-hydroxystyrene) or similar polymer with a low dispersity ornarrow dispersion can be synthesized by controlled free radical orliving anionic polymerization.

The resin (A) can be an alkali-soluble resin having hydroxyl or carboxylgroups, some of which are replaced by acid labile groups such that thesolubility in an alkaline developer changes as a result of severing ofthe acid labile groups under the action of an acid generated by thephotoacid generator upon exposure to radiation.

In the chemical amplification type resist composition, an appropriateamount of (B) the photoacid generator comprising an a compound of one offormulas I-II added is from about 0.5 part to about 20 parts by weight,and typically from about 1 to about 10 parts by weight, per 100 parts byweight of the solids in the composition. The photoacid generators may beused alone or as admixture of two or more types. The transmittance ofthe resist film can be controlled by using a photoacid generator havinga low transmittance at the exposure wavelength and adjusting the amountof the photoacid generator added.

Component B: Photoacid Generator Compounds (PAGs)

The photoacid generator compound can be a compound of any one offormulas I-XI described herein. Several general and specific examples ofuseful PAGs are described and illustrated in the Examples section and inFIGS. 2 and 3.

Component (C): Solvent

Component (C) can be an organic solvent. Illustrative, non-limitingexamples include butyl acetate, amyl acetate, cyclohexyl acetate,3-methoxybutyl acetate, methyl ethyl ketone, methyl amyl ketone,cyclohexanone, cyclopentanone, 3-ethoxyethyl propionate, 3-ethoxymethylpropionate, 3-methoxymethyl propionate, methyl acetoacetate, ethylacetoacetate, diacetone alcohol, methyl pyruvate, ethyl pyruvate,propylene glycol monomethyl ether, propylene glycol monoethyl ether,propylene glycol monomethyl ether propionate, propylene glycol monoethylether propionate, ethylene glycol monomethyl ether, ethylene glycolmonoethyl ether, diethylene glycol monomethyl ether, diethylene glycolmonoethyl ether, 3-methyl-3-methoxybutanol, N-methyl-pyrrolidone,dimethylsulfoxide, γ-butyrolactone, propylene glycol methyl etheracetate, propylene glycol ethyl ether acetate, propylene glycol propylether acetate, methyl lactate, ethyl lactate, propyl lactate, andtetramethylene sulfone. In one embodiment, the propylene glycol alkylether acetates and alkyl lactates are used in the compositions of theinvention.

The alkyl groups of the propylene glycol alkyl ether acetates can be of1 to about 4 carbon atoms, for example, methyl, ethyl and propyl.Propylene glycol alkyl ether acetates include 1,2- and 1,3-substitutedderivatives and each includes up to about three isomers, depending onthe combination of substituted positions, which may be used alone or inadmixture. The alkyl groups of the alkyl lactates can be of 1 to 4carbon atoms, for example, methyl, ethyl and propyl. These solvents maybe used alone or in admixture. In one embodiment, a useful solventsystem is a mixture of a propylene glycol alkyl ether acetate and analkyl lactate. The mixing ratio of the propylene glycol alkyl etheracetate and the alkyl lactate can be a mixture of about 50 to about 99parts by weight of the propylene glycol alkyl ether acetate with about50 to about 1 part by weight of the alkyl lactate. The solvent mixtureof the propylene glycol alkyl ether acetate and the alkyl lactate mayfurther contain one or more other solvents.

Component (D): Additional Photoacid Generator Compound

In one embodiment, the resist composition further contains component(D), a compound capable of generating an acid upon exposure to highenergy radiation, that is, a second photoacid generator other than thephotoacid generator (B). The second photoacid generators includesulfonium salts and iodonium salts as well as sulfonyldiazomethane,N-sulfonyloxyimide, benzoinsulfonate, nitrobenzylsulfonate, sulfone, andglyoxime derivatives. They may be used alone or in admixture of two ormore. Preferred component (D) photoacid generators used herein aresulfonium salts and iodonium salts.

In the resist composition comprising (B), a compound of one of formulasI-II, as the first photoacid generator, an appropriate amount of thesecond photoacid generator (D) is 0 to about 20 parts, and especiallyabout 1 to about 10 parts by weight per 100 parts by weight of thesolids in the composition. The second photoacid generators may be usedalone or in admixture of two or more. The transmittance of the resistfilm can be controlled by using a (second) photoacid generator having alow transmittance at the exposure wavelength and adjusting the amount ofthe photoacid generator added.

Component (E): Base

The basic compound used as component (E) can be a compound capable ofsuppressing the rate of diffusion when the acid generated by thephotoacid generator diffuses within the resist film. The inclusion ofthis type of basic compound holds down the rate of acid diffusion withinthe resist film, resulting in better resolution. In addition, it cansuppress changes in sensitivity following exposure and can reducesubstrate and environment dependence, as well as improve the exposurelatitude and the pattern profile.

Examples of basic compounds include primary, secondary, and tertiaryaliphatic amines, mixed amines, aromatic amines, heterocyclic amines,carboxyl group-bearing nitrogenous compounds, sulfonyl group-bearingnitrogenous compounds, hydroxyl group-bearing nitrogenous compounds,hydroxyphenyl group-bearing nitrogenous compounds, alcoholic nitrogenouscompounds, amide derivatives, imide derivatives, and combinationsthereof.

The basic compounds may be used alone or in admixture of two or more.The basic compound is preferably formulated in an amount of 0 to about 2parts, and especially about 0.01 to about 1 part by weight, per 100parts by weight of the solids in the resist composition. The use of morethan about 2 parts of the basis compound can result in a lowsensitivity.

Component (F)

Illustrative examples of the organic acid derivatives (F) include, butare not limited to, organic acid derivatives including4-hydroxyphenylacetic acid, 2,5-dihydroxyphenylacetic acid,3,4-dihydroxyphenylacetic acid, 1,2-phenylenediacetic acid,1,3-phenylenediacetic acid, 1,4-phenylenediacetic acid,1,2-phenylenedioxydiacetic acid, 1,4-phenylenedipropanoic acid, benzoicacid, salicylic acid, 4,4-bis(4′-hydroxy-phenyl)valeric acid,4-tert-butoxyphenylacetic acid, 4-(4′-hydroxyphenyl)butyric acid,3,4-dihydroxymandelic acid, 4-hydroxymandelic acid, and combinationsthereof. In certain embodiments, salicylic acid and4,4-bis(4′-hydroxyphenyl)valeric acid are employed. They may be usedalone or in admixture of two or more.

In the resist composition comprising a compound of one of formulas I-II,the organic acid derivative can be formulated in an amount of up toabout 5 parts, and especially up to about 1 part by weight, per 100parts by weight of the solids in the resist composition. The use of morethan about 5 parts of the organic acid derivative can result in a lowresolution. Depending on the combination of the other components in theresist composition, the organic acid derivative may be omitted.

Component (G): Dissolution Inhibitor

In one preferred embodiment, the resist composition further contains (G)a compound with a molecular weight of up to about 3,000 which changesits solubility in an alkaline developer under the action of an acid,e.g., a dissolution inhibitor. Typically, a compound obtained bypartially or entirely substituting acid labile substituents on a phenolor carboxylic acid derivative having a molecular weight of up to about2,500 is added as the dissolution inhibitor.

In the resist composition comprising a compound of one of formulas I-II,an appropriate amount of the dissolution inhibitor (G) is up to about 20parts, and especially up to about 15 parts by weight per 100 parts byweight of the solids in the composition. With more than about 20 partsof the dissolution inhibitor, the resist composition becomes less heatresistant because of an increased content of monomer components.

Component (H): Alkali-Soluble Resin

Component (B), a compound of one of formulas I-II, can also be used in achemical amplification negative-working resist composition. Thiscomposition further contains an alkali-soluble resin as component (H),examples of which are described above in the description of component(A), though the alkali-soluble resins are not limited thereto.

In various embodiments, the alkali-soluble resin can bepoly(p-hydroxystyrene), partially hydrogenated p-hydroxystyrenecopolymers, p-hydroxystyrene-styrene copolymers,p-hydroxystyrene-acrylic acid copolymers, andp-hydroxystyrene-methacrylic acid copolymers, a dendritic and/orhyperbranched polymer of the foregoing polymers, or combinationsthereof.

The alkali-soluble resin polymer can have a weight average molecularweight (Mw) of about 3,000 to about 100,000. Many polymers with Mw ofless than about 3,000 do not perform well in heat resistance and filmformation. Many polymers with Mw of more than 100,000 give rise toproblems with respect to dissolution in the resist solvent anddeveloper. The polymer can have a dispersity (Mw/Mn) of up to about 3.5,and more preferably up to about 1.5. With a dispersity of more thanabout 3.5, resolution is sometimes lower than is desired. Although thepreparation method is not critical, a poly(p-hydroxystyrene) or similarpolymer with a low dispersity or narrow dispersion can be synthesized bycontrolled free radical or living anionic polymerization.

To impart a certain function, suitable substituent groups can beintroduced into some of the phenolic hydroxyl and carboxyl groups on theacid labile group-protected polymer. Various embodiments includesubstituent groups for improving adhesion to the substrate, substituentgroups for improving etching resistance, and especially substituentgroups that are relatively stable against acid and alkali and areeffective for controlling dissolution rate such that the dissolutionrate in an alkali developer of unexposed and low exposed areas of aresist film does not increase to an undesirable level. Illustrativenon-limiting substituent groups include 2-hydroxyethyl, 2-hydroxypropyl,methoxymethyl, methoxycarbonyl, ethoxycarbonyl, methoxycarbonylmethyl,ethoxycarbonylmethyl, 4-methyl-2-oxo-4-oxolanyl,4-methyl-2-oxo-4-oxanyl, methyl, ethyl, n-propyl, iso-propyl, n-butyl,sec-butyl, acetyl, pivaloyl, adamantyl, isobornyl, and cyclohexyl. It isalso possible to introduce acid-decomposable substituent groups such ast-butoxycarbonyl and relatively acid-undecomposable substituent groupssuch as t-butyl and t-butoxycarbonylmethyl.

An acid crosslinking agent capable of forming a crosslinked structureunder the action of an acid is also contained in the negative resistcomposition. Typical acid crosslinking agents are compounds having atleast two hydroxymethyl, alkoxymethyl, epoxy or vinyl ether groups in amolecule. Substituted glycoluril derivatives, urea derivatives, andhexa(methoxymethyl)melamine compounds are suitable as the acidcrosslinking agent in the chemically amplified negative-resistcomposition comprising the photoacid generators described herein.Examples of acid crosslinking agents includeN,N,N′,N′-tetramethoxymethylurea, hexamethoxymethylmelamine,tetraalkoxymethyl-substituted glycoluril compounds such astetrahydroxymethyl-substituted glycoluril andtetramethoxy-methylglycoluril, and condensates of phenolic compoundssuch as substituted or unsubstituted bis(hydroxymethylphenol) compoundsand bisphenol A with epichlorohydrin. In certain specific embodiments,the acid crosslinking agent can be one or more of1,3,5,7-tetraalkoxy-methylglycolurils such as1,3,5,7-tetramethoxymethylglycoluril,1,3,5,7-tetrahydroxymethylglycoluri-1,2,6-dihydroxymethyl-p-cresol,2,6-dihydroxymethylphenol, 2,2′,6,6′-tetrahydroxymethyl-bisphenol A,1,4-bis[2-(2-hydroxypropyl)]benzene, N,N,N′,N′-tetramethoxymethylurea,and hexamethoxymethylmelamine. In the resist composition, an appropriateamount of the acid crosslinking agent is about 1 to about 25 parts, andespecially about 5 to about 15 parts by weight per 100 parts by weightof the solids in the composition. The acid crosslinng agents may be usedalone or in admixture of two or more.

Component (J): Low Molecular Weight Alkali-Soluble Compound

Component (J), an alkali-soluble compound having a molecular weight ofup to about 2,500 can be blended into the chemical amplification typenegative-working resist composition. The compound should preferably haveat least two phenol and/or carboxyl groups. Illustrative non-limitingexamples include cresol, catechol, resorcinol, pyrogallol, fluoroglycin,bis(4-hydroxyphenyl)methane, 2,2-bis(4′-hydroxyphenyl)propane,bis(4-hydroxyphenyl)sulfone, 1,1,1-tris(4′-hydroxyphenyl)ethane,1,1,2-tris(4′-hydroxyphenyl)ethane, hydroxybenzophenone,4-hydroxyphenylacetic acid, 3-hydroxyphenylacetic acid,2-hydroxyphenylacetic acid, 3-(4-hydroxyphenyl)propionic acid,3-(2-hydroxyphenyl)propionic acid, 2,5-dihydroxyphenylacetic acid,3,4-dihydroxyphenylacetic acid, 1,2-phenylenediacetic acid,1,3-phenylenediacetic acid, 1,4-phenylenediacetic acid,1,2-phenylenedioxydiacetic acid, 1,4-phenylenedipropanoic acid, benzoicacid, salicylic acid, 4,4-bis(4′-hydroxyphenyl)valeric acid,4-tert-butoxyphenylacetic acid, 4-(4-hydroxyphenyl)butyric acid,3,4-dihydroxymandelic acid, and 4-hydroxymandelic acid. In certainspecific embodiments, component (J) is salicylic acid and/or4,4-bis(4′-hydroxyphenyl)valeric acid. The compounds can be used aloneor in admixture of two or more. The addition amount can be 0 to about 20parts, preferably about 2 to about 10 parts by weight per 100 parts byweight of the solids in the composition.

Additional Optional Components

In the resist composition according to the invention, there may beadditional additives such as a surfactant for improving coating, and/ora light absorbing agent for reducing diffuse reflection from thesubstrate.

Illustrative non-limiting examples of the surfactant include nonionicsurfactants, for example, polyoxyethylene alkyl ethers such aspolyoxyethylene lauryl ether, polyoxyethylene stearyl ether,polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether,polyoxyethylene alkylaryl ethers such as polyoxyethylene octylphenolether and polyoxyethylene nonylphenol ether, polyoxyethylenepolyoxypropylene block copolymers, sorbitan fatty acid esters such assorbitan monolaurate, sorbitan monopalmitate, and sorbitan monostearate,and polyoxyethylene sorbitan fatty acid esters such as polyoxyethylenesorbitan monolaurate, polyoxyethylene sorbitan monopalmitate,polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitantrioleate, and polyoxyethylene sorbitan tristearate; fluorochemicalsurfactants such as EFTOP EF301, EF303 and EF352 (Tohkem Products K.K.),Megaface F171, F172 and F173 (Dai-Nippon Ink & Chemicals K.K.), FloradeFC430 and FC431 (Sumitomo 3M K.K.), Asahiguard AG710, Surflon S-381,S-382, SC101, SC102, SC103, SC104, SC105, SC106, Surfynol E1004, KH-10,KH-20, KH-30 and KH-40 (Asahi Glass K.K.); organosiloxane polymersKP341, X-70-092 and X-70-093 (Shin-Etsu Chemical Co., Ltd.), acrylicacid or methacrylic acid Polyflow No. 75 and No. 95 (Kyoeisha UshiKagaku Kogyo K.K.). In certain specific embodiments, FC430, SurflonS-381 and Surfynol E1004 are employed. These surfactants may be usedalone or in combination with others.

In the resist composition, the surfactant can be formulated in an amountof up to about 2 parts, and especially up to about 1 part by weight, per100 parts by weight of the solids in the resist composition.

A UV absorber can be added to the resist composition. An appropriateamount of UV absorber blended is 0 to about 10 parts, more preferablyabout 0.5 to about 10 parts, most preferably about 1 to about 5 parts byweight per 100 parts by weight of the base resin.

For the microfabrication of integrated circuits, any well-knownlithography may be used to form a resist pattern from the chemicalamplification positive- or negative-working resist composition.

Substrates

The composition can be applied to a substrate (e.g., Si, SiO₂, SiN,SiON, TiN, WSi, BPSG, SOG, organic anti-reflecting film, etc.) by asuitable coating technique such as spin coating, roll coating, flowcoating, dip coating, spray coating or doctor coating. The coating canbe prebaked on a hot plate at a temperature of about 60° C. to about150° C. for about 1 to about 10 minutes, typically about 80° C. to about120° C. for about 1 to 5 minutes. The resulting resist film is generallyabout 0.1 to about 2.0 μm thick. With a mask having a desired patternplaced above the resist film, the resist film can then be exposed toactinic radiation, typically having an exposure wavelength of up toabout 300 nm, such as UV, deep-UV, electron beams, x-rays, excimer laserlight, γ-rays or synchrotron radiation in an exposure dose of about 1 to200 mJ/cm², typically about 10 to 100 mJ/cm². The film can be furtherbaked on a hot plate at about 60° C. to about 150° C. for about 1 to 5minutes, typically about 80° C. to about 120° C. for about 1 to 3minutes (post-exposure baking=PEB).

Thereafter the resist film can be developed with a developer in the formof an aqueous base solution, for example, about 0.1% to about 5%,typically about 2% to about 3% aqueous solution of tetramethylammoniumhydroxide (TMAH) for about 0.1 to 3 minutes, typically about 0.5 toabout 2 minutes by conventional techniques such as dipping, puddling, orspraying. In this way, a desired resist pattern can be formed on thesubstrate. It is appreciated that the resist composition of theinvention is well suited for micro-patterning using such actinicradiation as deep UV with a wavelength of about 254 μm to about 193 nm,13.4 nm (EUV), electron beams, x-rays, excimer laser light, y-raysand/or synchrotron radiation. With any of the above-described parametersoutside the above-described range, the process may sometimes fail toproduce the desired pattern.

General Synthetic Procedures for Photoacid Generator Compounds

The useful PAGs described herein can be prepared as outlined below inthe Examples and by using techniques and reaction sequences known tothose of skill in the art.

The compounds described herein can be prepared by any of the applicabletechniques of organic synthesis. Many such techniques are well known inthe art. However, many of the known techniques are elaborated inCompendium of Organic Synthetic Methods (John Wiley & Sons, New York)Vol. 1, Ian T. Harrison and Shuyen Harrison (1971); Vol. 2, Ian T.Harrison and Shuyen Harrison (1974); Vol. 3, Louis S. Hegedus and LeroyWade (1977); Vol. 4, Leroy G. Wade Jr., (1980); Vol. 5, Leroy G. WadeJr. (1984); and Vol. 6, Michael B. Smith; as well as March, J., AdvancedOrganic Chemistry, 3rd Edition, John Wiley & Sons, New York (1985);Comprehensive Organic Synthesis. Selectivity, Strategy & Efficiency inModern Organic Chemistry, In 9 Volumes, Barry M. Trost, Editor-in-Chief,Pergamon Press, New York (1993); Advanced Organic Chemistry, Part B:Reactions and Synthesis, 4th Ed.; Carey and Sundberg; KluwerAcademic/Plenum Publishers: New York (2001); Advanced Organic Chemistry,Reactions, Mechanisms, and Structure, 2nd Edition, March, McGraw Hill(1977); Protecting Groups in Organic Synthesis, 2nd Edition, Greene, T.W., and Wutz, P. G. M., John Wiley & Sons, New York (1991); andComprehensive Organic Transformations, 2nd Edition, Larock, R. C., JohnWiley & Sons, New York (1999).

It is appreciated that those of skill in synthetic organic chemistryunderstand that reagents are typically referred to by the chemical namesthat they bear or formulae that represent their structures prior toaddition to a chemical reaction mixture, even though the chemicalspecies actually present in the reaction mixture or involved in thereaction may be otherwise. While a compound may undergo conversion to acompound bearing a different name or represented by a different formulaprior to or during a specified reaction step, reference to thesecompounds by their original name or formula is acceptable and iswell-understood by those of skill in the art of organic chemistry.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

Specific ranges, values, and embodiments provided below are forillustration purposes only and do not otherwise limit the scope of theinvention, as defined by the claims.

The following literature is incorporated herein by reference:

PAG General Reviews:

Shirai, M.; Tsunooka, M., “Photoacid and photobase generators: chemistryand applications to polymeric materials” Progress in Polymer Science1996, 21(1), 1-45.

Shirai, M.; Suyama, K.; Okamura, H.; Tsunooka, M., “Development of novelphotosensitive polymer systems using photoacid and photobase generators”Journal of Photopolymer Science and Technology 2002, 15(5), 715-730.

Nitobenzyl Core:

Houlihan, F. M.; Neenan, T. X.; Reichmanis, E.; Kometani, J. M.; Chin,T., “Design, synthesis, characterization, and use of all-organic,nonionic photogenerators of acid” Chemistry of Materials 1991, 3(3),462-71.

Alunad Hasan, Klaus-Peter Stengele, Heiner Giegrichl, Paul Cornwell,Kenneth R. Isham, Richard A. Sachleben, Wolfgang Pfleiderer, and RobertS. Foote, Photolabile Protecting Groups for Nucleosides: Synthesis andPhotodeprotection Rates, Tetrahedron, Vol. 53, No. 12, pp. 4247-4264,1997.

Serafinowski and Garland, J Am. Chem. Soc. 2003, 125, 962-965.

Imide Core:

Iwashima, C.; Imai, G.; Okamura, H.; Tsunooka, M.; Shirai, M., “Sythesisof i- and g-line sensitive photoacid generators and their application tophotopolymer systems” Journal of Photopolymer Science and Technology2003, 16(1), 91-96.

Okamura, Haruyuki; Sakai, Koichi; Tsunooka, Masahiro; Shirai, Masamitsu;Fujiki, Tsuyoshi; Kawasaki, Shinich; Yamada, Mitsuaki. I-line sensitivephotoacid generators and their use for photocrosslinking ofpolysilane/diepoxyfluorene blend. Journal of Photopolymer Science andTechnology (2003), 16(1), 87-90.

Okamura, Haruyuki; Sakai, Koichi; Tsunooka, Masahiro; Shirai, Masamitsu.Evaluation of quantum yields for decomposition of 1-line sensitivephotoacid generators. Journal of Photopolymer Science and Technology(2003), 16(5), 701-706.

Okamura, Haruyuki; Matsumori, Ryosuke; Shirai, Masamitsu. I-linesensitive photoacid generators having thianthrene skeleton. Journal ofPhotopolymer Science and Technology (2004), 17(1), 131-134.

Also incorporated by reference into this disclosure are U.S. Pat. Nos.6,316,639 (Fritz-Langhals; “Process for the preparation of cyclicN-hydroxy-dicarboximides”); 6,582,879 (Choi et al.; “Reactive photoacid-generating agent and heat-resistant photoresist composition withpolyamide precursor”); 6,692,893 (Ohsawa et al.); 7,105,267 (Hatakeyamaet al.); and 7,163,776 (Sasaki et al.); and U.S. Patent ApplicationPublication No. 2005/0186505 (Kodama et al.).

The following Examples are intended to illustrate the above inventionand should not be construed as to narrow its scope. One skilled in theart will readily recognize that the Examples suggest many other ways inwhich the present invention could be practiced. It should be understoodthat many variations and modifications may be made while remainingwithin the scope of the invention.

EXAMPLES

The variable groups defined in the following Examples are forillustrative purposes, and the embodiments described in the Examples arenot limited to those values in other embodiments. Certain groups,ranges, and specific variables that can be employed in the variousembodiments are further described above in the summary and detaileddescription.

Example 1 General Synthesis of an Ionic Photoacid Generator

Ionic photoacid generators according to various embodiments can beprepared as illustrated below in Scheme 1-1.

The synthetic procedure to prepare ionic photoacid generator (1-IV) witha perfluorooxyalkyl group which is in turn attached to lactone ring viaan alkyl linkage is summarized below. Reaction of halogen containingperfluorooxyalkyl sulfonyhalide (1-I) with alkali metal hydroxideresults in perfluorooxyalkylsulfonate (1-II). Compound 1-III wasobtained by reacting 1-II with the sodium salt of an alkenoic acid inthe presence of dehalogeno-alkylating reagents. Finally an exchangereaction of sulfonate (1-III) with a photoactive cation in an aqueous oraqueous/organic solvent system affords new ionic photoacid generator1-IV, wherein the variables are as defined in the Summary above.

See Hu and Qing, J. Org. Chem, 1991, 56, 6348-6351; Zou et al.,Tetrahedron, 2003, 59, 2555-2560; Imazeki et al., Synthesis, 2004, 10,1648-1654; and Crivello and Lam, Macromolecules, 1977, 10, 1307-1315 forrelated synthetic techniques and procedures.

Certain specific examples of ionic PAGs include compounds I-1 through1-2, including the various stereoisomers of compounds 1-3 and 1-4:

The methyl group of compounds 1-3 and 1-4 provides advantageousproperties the PAGs including increased melting points andcrystallinity. Compounds 1-1 and 1-2 tend to be oils and not crystallinesolids.

Thermal and optical properties of iodonium PAG 1-2 and variouscomparative PAGs are shown below in Table 1.

TABLE 1 Thermal and Optical Properties Acid size^(a) T_(d) T_(m) ε₂₄₈^(b) PAG (cm³) (° C.) (° C.) (cm² · mol⁻¹)

146 205 154 NA

241 190 134 6015

240 164 104 5220

232 165  −20^(c) 5400

162 NA  78 4200

272 NA NA NA ^(a)Estimated by ACD lab software; ^(b)Measured inacetonitrile; ^(c)Transparent oil at room temperatures (23° C.).

Other comparative data of PAG properties are shown in Table 2.

TABLE 2 PAG Property Comparisons Acid Molar Volume Sulfonate AnionSulfonate Anion Acid (cm³) M_(W) F wt % H wt % PFOS

272.1 500.13 64.58 — PFBuS

162.3 300.10 59.98 — norbornyl-

240.0 392.26 38.85 2.83 lactone-

232.0 396.21 38.46 1.79

Other useful PAGs include compounds of formula X:

wherein

R_(f) is a diradical carbon chain comprising one to about 20 carbonatoms wherein the chain can be optionally interrupted by one to fiveoxygen atoms, and each carbon atom is substituted with zero to two halogroups, typically two fluoro groups;

each of R₃-R₈ is independently H, alkyl, cycloalkyl, heterocycle, aryl,or heteroaryl;

n₂ is 0, 1, 2, 3, 4, or 5;

n₃ is 1 or 2;

A₁ is I or S and when A₁ is I, then n₁ is 2 and when A₁ is S, then n₁ is3;

each Ro is independently alkyl, cycloalkyl, heterocycle, aryl, orheteroaryl, each optionally substituted with one to about fivesubstituents; and

A₂ is O and n₄ is 1, or A₂ is N and n₄ is 2.

As is readily understood by one skilled in the art, the chain thatincludes the fluorinated carbons can be attached to the lactone group atany viable position on the lactone ring. In various embodiments, R_(f)can be fluorinated alkyl groups optionally interrupted by oxygen atoms,for example —CF₂CF₂—O—CF₂CF₂— or —(CF₂)_(m) wherein m is 1 to about 10(or 1 to about 8, or 1 to about 6). The lactone ring can optionally haveone cite of unsaturation.

Still other useful PAGs include compounds of formula XI:

wherein R₉ can be L-R* wherein L can be —CH₂—, —NH—, or —O—; R* can bealkyl, cycloalkyl, cycloalkoxy, alkoxy, heterocycle, aryl, heteroaryl;and R₁₀ can be H, alkyl, or acyloxy. In various embodiments, theheterocycle is a cycloether. In other embodiments, the cycloalkyl isnorbornyl or adamantly. I certain embodiments, R₁₀ is tbutyl or an alkylester, for example, methyl carboxylate.

Example 2 Synthesis of an Ionic Photoacid Generator

Ionic photoacid generators according to various embodiments can beprepared as illustrated below in Scheme 2-1.

Ionic photoacid generator VIII with a perfluorooxyalkly group directlyattached to an alkyl or cycloalkyl group can be synthesized asillustrated above wherein X and X′ are halo, R is alkyl, cycloalkyl,heterocycle, aryl, or heteroaryl, each optionally substituted with oneto about five substituents. Sulfonyl halide V (commercially available orsynthesized in one to about five steps) can be converted to compound VIby reacting with a substituted alkene in the presence ofdehalogeno-alkylating reagents. Compound VI was converted to sulfonateVII by direct oxidation with an alkali metal hydroxide, for example,NaOH or KOH. The resulting sulfonate obtained was then subjected to anexchange reaction with a photoactive cation in an aqueous or anaqueous/organic solvent system to afford new ionic photoacid generatorVIII, wherein A₁ is iodonium or sulfonium, each (Ro) is independentlyalkyl, cycloalkyl, heterocycle, aryl, or heteroaryl, each optionallysubstituted with one to about five substituents, and n₁ is 2 or 3.

See Feiring and Wonchoba, Journal of Fluorine Chemistry, 2000, 105, 129;De Vleeschauwer and Gauthier, Synlet, 1997, 375-377; Blonty, TetrahedronLetters, 2003, 44, 1499-1501; Feiring, Journal of Organic Chemistry,1985, 50, 3269-3274; Hu and Qing, J. Org. Chem, 1991, 56, 6348-6351; andCrivello and Lam, Macromolecules, 1977, 10, 1307-1315 for relatedsynthetic techniques and procedures.

Example 3 General Synthesis of an Ionic Photoacid Generator

Ionic photoacid generators according to various embodiments can beprepared as illustrated below in Scheme 3-1.

A simplified synthetic procedure to obtain an ionic photoacid generatorwith a perfluoro or aryl group directly attached to the sulfonate groupis described below. A sulfonyl chloride (commercially available orsynthesized in one to about five steps) was converted to sulfonateeither by direct oxidation with an alkali metal hydroxide or byhydrolysis followed by neutralization with silver carbonate. Thesulfonate obtained was then subjected to an exchange reaction with aphotoactive cation in an aqueous or an aqueous/organic solvent system toafford a new ionic photoacid generator, wherein R₂ can be alkyl,cycloalkyl, heterocycle, aryl, or heteroaryl, each optionallysubstituted with one to about five substituents, and A₁, (Ro), n₁ can bedefined as in Example 2.

See Feiring and Wonchoba, Journal of Fluorine Chemistry, 2000, 105, 129;Vleeschauwer and Gauthier, Synlet, 1997, 375-377; Blonty, TetrahedronLetters, 2003, 44, 1499-1501; Houlihan et al., F. M.; Chemistry ofMaterials 1991, 3 (3), 462-71; Hu and Qing, J Org Chem, 1991, 56,6348-6351; and Crivello and Lam, Macromolecules, 1977, 10, 1307-1315 forrelated synthetic techniques and procedures.

Example 4 Synthesis of Non-Ionic Photoacid Generators

Nonionic photoacid generators according to various embodiments can beprepared as illustrated below in Scheme 4-1.

A sulfonyl chloride (commercially available or synthesized from thecorresponding precursors) can be used to prepare nonionic PAGs. Theimide based PAGs 4-I were prepared by reaction of the correspondingN-hydroxyimide with an appropriate sulfonyl chloride in the presence ofa base. A nitrobenzyl PAG 4-II can be synthesized either by reacting asilver sulfonate with nitrobenzyl bromide or by reacting a nitrobenzylalcohol with a sulfonyl chloride in the presence of coupling reagents.

In various embodiments, R₂, R₃, G₁, G₂, G₃ and G₄ can each independentlybe alkyl, cycloalkyl, heterocycle, aryl, or heteroaryl, each optionallysubstituted with one to about five substituents. For example, in certainembodiments R₂ can be (C₁-C₈)alkyl, or phenyl, each optionallysubstituted, for example, with one to five substituents. In certainembodiments, R₃ can be H or (C₁-C₆)alkyl. In certain embodiments, G₁ andG₂ can be H, halo, alkyl, alkoxy, carboxy, cyano, acyl, acyloxy,trifluoromethyl, amino, or nitro. In certain embodiments, G₃ and G₄ caneach independently be H, (C₁-C₈)alkyl, acyl, aroyl, or a nitrogenprotecting group; or, G₃ and G₄ can form a heteroaryl or heterocyclegroup together with the nitrogen atom to which they are attached.

See Feiring and Wonchoba, J. Fluorine Chemistry, 2000, 105, 129; DeVleeschauwer and Gauthier, Synlet, 1997, 375-377; Blonty, TetrahedronLett, 2003, 44, 1499-1501; Iwashima et al., J. Photopolymer Science andTechnology 2003, 16 (1), 91-96; Okamura et al., J. Photopolymer Scienceand Technology 2003, 16 (1), 87-90; Okamura et al., J. PhotopolymerScience and Technology 2003, 16 (5), 701-706; Okamura et al., J.Photopolymer Science and Technology 2004, 17 (1), 131-134; Houlihan etal., Chemistry of Materials 1991, 3 (3), 462-71 for related synthetictechniques and procedures.

Various nonionic PAGs can be prepared as illustrated in Scheme 4-2below.

wherein G is H, halo, nitro, amino, alkyl, alkoxy, cycloalkyl,heterocycle, aryl, or heteroaryl; and wherein one to about five hydrogenatoms on a given G group can be optionally substituted.

Various other nonionic PAGs can be prepared as illustrated in Schemes4-3 and 4-4:

Other nonionic PAGs include the compounds of Scheme 4-5 and phenylsubstitution stereoisomeric derivatives thereof.

Example 5 Nonionic Photoacid Generating Compounds with FunctionalizedFluoroorganic Sulfonate Motif

Photoacid generators (PAG) improve sensitivity and offer flexibility indesigning chemically amplified resist (CAR) systems. Acid generatingefficiency (acid generation mechanism, physico-chemical properties andlithography performance) is strongly dependent on PAG structures.Nonionic photoacid generators (PAGs) with an appropriate combination ofphotosensitive chromophore and photoacid generating motif are of greatinterest because they offer a wider range of absorption, lithographicperformance, solubility, and thermal properties than many widely usedionic PAGs. Any nonionic PAG that is expected to be viable in commercialapplications, including lithographic techniques, should be free ofperfluorooctyl sulfonate (PFOS) because of the environmental concernsassociated with PFOS PAGs. The nonionic photoacid generators describedherein can be photosensitive fluoroorganic sulfonic esters of amides,imides, nitrobenzyl groups, and their derivatives (e.g., these groupssubstituted with one to five substituents, which are described above inthe Detailed Dsecription). Generic examples are illustrated below inScheme 5-1. Initial photosensitive chromophores and fluoroorganic groupsuseful for preparing nonionic PAGs of Scheme 5-1 are shown in Schemes5-2 and 5-3.

wherein

-   -   M=a non-metallic atom that is a member of one or more rings that        contain 2 to about 16 other ring atoms, which may include        heteroatoms (e.g., N or O), and which may optionally possess one        to about five substituents;    -   R₁-R₄═H, halo, nitro, amino, alkyl, alkoxy, cycloalkyl,        heterocycle, aryl, or heteroaryl;        -   Q=aryl optionally substituted with one to about five            substituents.

In certain embodiments, R₂ is H, methyl, phenyl, or methoxyphenyl (anyone of ortho-, meta-, or para-). In various embodiments, R₃ is H, nitro,F, or trifluoromethyl. In various embodiments, R₄ can be H, methoxy,dimethylamino, nitro, or bromo.

Several reports have been documented concerning developing nonionic PAGswith improved physico-chemical properties. However, most reportsconcentrate on the chromophore to alter their absorption range or thethermal properties of the nonionic PAGs. A design disclosed in thisExample focuses on improving sensitivity and lithography performance ofthe nonionic PAGs. A photoacid group can be employed, which is acombination of partially, semi-, or unfluorinated sulfonate withfunctional groups. The acidity and miscibility of the PAG can be alteredby functional groups or a combination of reduced number of fluorineatoms with functional groups that in turn improve the sensitivity of thePAG as well as its distribution in the polymer matrix. The functionalgroups selected can help to reduce particle formation in solution andcan increase uniform detect-free, thin film formation.

In order to reduce the outgassing/contamination and photoacid diffusion,a photoacid group or photosensitive groups can be anchored toflexible/rigid oligomeric molecules. To further improve the sensitivityand lithographic performance, nonionic PAGs with multiple or twodifferent photoacid structures are being developed. In addition tophotoacid structure design, the absorption and thermal properties of thePAG can be controlled by taking advantage of various substituent effectsand symmetry of the structures. These nonionic PAGs are non-metallic innature and can produce sulfonic acids that contain reduced amount offluorine and functional groups upon irradiation. These PAGs areenvironmentally friendly, as well as semiconductor process friendly.Their lithographic performances are enhanced compared to conventionalPAGs because the functionalized groups are incorporated into thenonionic PAGs, which improves several properties of these PAGs,including solubility, sensitivity, and optical properties.

Example 6 Photoacid Generators (PAGs) Based on Novel Fluorinated Groups

Chemically amplified resist (CAR) materials containing photoacidgenerators (PAGs) have facilitated the semiconductor manufacturingprocess from 250 nm to 90 nm. Even in 193 nm and next generationlithography (NGL), it is also viable to fabricate the continuinglydecreased feature size of microelectronics. Among the CAR system,photoacid generator (PAG) is a critical component. It generates acidonce absorbing a photon and then catalyzes numerous chemical reactionsin the exposed area of the resist film. Resist sensitivity or thephotospeed is thus increased dramatically (100 wafers/hour). PAGs basedon ionic and non-ionic molecules were developed. Both of them arecomposed of two parts, the acid precursor and the chromophore. Thechemical structure of PAG has great impact on the resist performances.For example, if a PAG is not homogeneously distributed in the resistfilm, it will lead to patterning profile problems such as T-topping,footing and skin formation. Acid diffusion is another important issue.In order to minimize the line width roughness (LWR), photoacid shouldhave suitable size to control the acid diffusion rate. Moreover, as thefeature size decreases in NGL, the contribution to patterning propertiesfrom PAG becomes more and more significant. If a PAG is not carefullyselected, it will result in patterning deviation and the poor deviceperformances. Besides the technical problems discussed above, PAGsshould be practically non-toxic and friendly to environment. In order totackle the technical and safety issues, a series of ionic and nonionicPAGs having novel functionalized acid precursors has been designed. Thetarget chemicals are revealed in this patent application. The structuresof certain specific and general ionic PAGs are listed in FIG. 2 and thestructures of certain specific and general nonionic PAGs are listed inFIG. 3.

An effective way to improve the resist performances and sensitivity isto develop new PAGs having novel chemical structures. Based on themodular design approach, functional groups were introduced intoperfluorinated acid precursors to control the acid size and volatilitywhile maintaining the acid strength. The functional groups for acidprecursors were selected to mimic the groups in the resist side chain sothat the PAG interacts with resist and distribute uniformly. The photogenerated acid is then able to diffuse at an optimum level.

For example, because 193 nm and EUV resist include γ-lactone and benzeneside groups, PAGs having lactone or aromatic groups are able todistribute uniformly in the polymer matrix, which leads to lowervariation in the resulting lithographic patternings. Furthermore, thepresence of strong PAG/polymer interaction reduces leaching levels ofthese PAGs when they are used in 193 immersion lithography.

These PAGs have good solubility in organic solvents widely used inmicrolithography, such as PGMEA, γ-butyrolactone and ethyl lactate. ThePAGs are thermally stable as most of NGL requires high activation energyresist. The thermal and absorption properties of the PAGs can becontrolled by balancing the composition of element. The designed PAGscan be used not only in semiconductor manufacturing but also in variouscoating applications. It is important that any PAG developed should benon-toxic and environmentally friendly. In contrast to PFOS-based PAGs,the PAG structures listed in this application contain significantlyreduced amounts of fluorine and are therefore less toxic to theenvironment and human health.

All literature and patent citations above are hereby expresslyincorporated by reference at the locations of their citation.Specifically cited sections or pages of the above cited works areincorporated by reference with specificity. The invention has beendescribed in detail sufficient to allow one of ordinary skill in the artto make and use the subject matter of the following Embodiments. It isapparent that certain modifications of the methods and compositions ofthe following Embodiments can be made within the scope and spirit of theinvention.

1. A compound of formula I:

wherein A₁ is I or S; n₁ is 2 when A₁ is I, and n₁ is 3 when A₁ is S;each Ro is independently alkyl, cycloalkyl, heterocycle, aryl, orheteroaryl, each optionally substituted with one to about fivesubstituents; A₂ is O or N; n₂ is 1 when A₂ is O and n₂ is 2 when A₂ isN; R_(f) is a diradical carbon chain comprising one to about 20 carbonatoms wherein the chain is optionally interrupted by one to five oxygenatoms, and each carbon atom is substituted with zero to two halo groups,or R_(f) is a direct bond; each R¹ is independently H, alkyl,cycloalkyl, heterocycle, aryl, or heteroaryl; n₃ is 0 to about 10; n₄ is1 or 2; n₅ is 0 to 7; and any aryl or heteroaryl of formula I isoptionally substituted with one to five halo, (C₁-C₆)alkyl, alkoxy,acyl, alkoxycarbonyl, alkoxyacyl, acyloxy, trifluoromethyl,trifluoromethoxy, hydroxy, cyano, carboxy, nitro, or —N(R²)₂ groups; anyalkyl, cycloalkyl, heterocycle, aryl, or heteroaryl is optionallysubstituted with one to five halo, (C₁-C₆)alkyl, alkoxy, acyl,alkoxyacyl, acyloxy, trifluoromethyl, trifluoromethoxy, hydroxy, cyano,carboxy, nitro, —N(R²)₂, or oxo groups; and each R² is independently H,alkyl, aryl, acyl, or aroyl.
 2. The compound of claim 1 wherein Ro isaryl or heteroaryl.
 3. The compound of claim 1 wherein at least onecarbon of R_(f) is substituted with two fluoro groups or R_(f) is adirect bond.
 4. The compound of claim 1 wherein R_(f) is —(CF₂)_(n)—wherein n is 1 to about 6, —C(CF₃)₂—, —(CF₂)—O—(CF₂)₂—O—(CF₂—,—(CF₂)₂—O—(CF₂)₂—, or a direct bond.
 5. The compound of claim 1 whereinn₃ is 1; n₄ is 1; and n₅ is
 0. 6. The compound of claim 1 wherein n₅ is1 and R¹ is (C₁-C₈)alkyl.
 7. The compound of claim 1 wherein n₅ is 1 andR¹ is methyl.
 8. The compound of claim 1 wherein the compound is


9. A compound of formula II:

wherein R₀ is alkyl, cycloalkyl, heterocycle, aryl, or heteroaryl,optionally substituted with one to about five substituents; R₁ and R₂are each independently H, alkyl, cycloalkyl, heterocycle, aryl, orheteroaryl; G¹ is H, halo, hydroxy, nitro, cyano, trifluoromethyl, ortrifluoromethoxy; each G² is independently alkyl, cycloalkyl,heterocycle, aryl, heteroaryl, halo, alkoxy, acyl, alkoxycarbonyl,alkoxyacyl, acyloxy, trifluoromethyl, trifluoromethoxy, hydroxy, cyano,carboxy, nitro, or —N(R²)₂ wherein each R² is independently H, alkyl,aryl, acyl, or aroyl; n is 0, 1, 2, 3, or 4; and any alkyl, cycloalkyl,heterocycle, aryl, or heteroaryl is optionally substituted with one tofive halo, (C₁-C₆)alkyl, alkoxy, acyl, alkoxyacyl, acyloxy,trifluoromethyl, trifluoromethoxy, hydroxy, cyano, carboxy, nitro,—N(R²)₂, or oxo groups.
 10. The compound of claim 9 wherein R₀ isoptionally substituted aryl.
 11. The compound of claim 9 wherein R₀ isan optionally substituted phenyl.
 12. The compound of claim 9 wherein R²is H.
 13. The compound of claim 9 wherein R¹ is not H.
 14. The compoundof claim 9 wherein G¹ is nitro.
 15. The compound of claim 9 wherein G¹is nitro at the ortho position with respect to the —C(R₁)(R₂)substituent.
 16. The compound of claim 9 wherein G² is F or —CF₃. 17.The compound of claim 9 wherein the compound is substituted with 2-6fluoro groups.
 18. The compound of claim 9 that is


19. The compound of claim 1 wherein the compound is a photoacidgenerator.
 20. A chemical amplification type resist compositioncomprising the photoacid generator of claim 19, a resin, and a solventsystem.
 21. A composition comprising a compound of claim 19 and a resinthat changes its solubility in an alkaline developer when contacted withan acid.
 22. A composition comprising a compound of claim 19 and acompound that is capable of generating an acid upon exposure toradiation and that is not a compound of claim
 19. 23. The composition ofclaim 20 further comprising a basic compound.
 24. A method to form apattern comprising: a) applying onto a substrate a resist compositioncomprising a compound of claim 19, to provide a substrate with acoating; b) heat treating the coating and exposing the coating to highenergy radiation or electron beam through a photo-mask; and c)optionally heat treating the exposed coating and developing the coatingwith a developer.